Although the association of diabetes and potency disorders is well recognized, there is limited information in the pathophysiology of erectile disorders in the diabetic male and few procedures that may assist the differential diagnosis between psychogenic and organic impotence. There is also an almost total lack of information concerning the influence of diabetes mellitus upon sexual function in the female patient. The overall objective of this application is to study sexual dysfunction in diabetic patients. Studies are proposed to gather data on the prevalence and nature of sexual problems in a population of female diabetics. For this purpose, a detailed semi-structured interview, a sexual history questionnaire and a self-report scale of sexual function will be completed by a group of female diabetics and a comparison group of non-diabetic patients. The second objective of the proposed research is to evaluate the diagnostic value of assessing nocturnal penile tumescence for the evaluation of potency disorders in diabetic male patients. For this purpose, the nocturnal erection pattern of four groups of subjects will be compared: diabetic men free from sexual disorders, diabetic men with erectile dysfunctions, psychologically impotent non-diabetic men and normal controls.